hey guys,
i have an 06 crewcab and just got a nelson pcm not too long ago.
well after about a month the check engine light came on and when i scanned it,it was crank variation not learned or some ****.well my friend works at a shop and he has done about 7 relearns,but mine will not re-learn.he is using a tech-2 for the re-learn.
the tech 2 says to rev the motor until the fuel cutoff kicks in,but we revved it to 5900 and no fuel cutoff so he let off.he said normally the trucks fuel cutoff is around 4000rpm,but not on my 06 and not on his 07 classic.
what do you guys think i should do?
can a dealer do the re-learn w/out erasing my tune?
thanks guys.
charles

 

Call Nelson first.

 

 

Nelson is going to tell you to take it to a shop and have the relearn done. The process is as you described. The pedal goes to the floor and you can not be scared to do it. Once it is on the floor after a few seconds the motor sputters and your done. That is the only way to do it.

 

mine did the same thing. i reved her up and after a few seconds it worked.

 

I've heard if you HPTuners you can do a relearn, i would like to know for my personal knowledge so i know if i can do it to someone else's truck.

 

How quickly did you rev it up? I've done relearn's on just about every model year truck with no problems, they've all stumbled at 4000rpms. Be sure to do it over the course of 3-4 seconds and not a quick stab of the throttle.

Justin

 

what if the fuel-cutoff rpm was changed in the tune, wouldn't that affect if it relearns or not?

 

No it shouldn't, as the 4000rpm fuel cutoff used by the crank relearn is independent of the fuel cutoff used by the rev limiter. The crank relearn is only a momentary cutoff, as if were to stay in the throttle, after the short stumble, the engine would continue to rev up.

It's possible that the original poster was unable to complete the process due to necessary conditions not having been met... eg, throttle position, temp, etc.

 

i guess i'll have to go back and try it again.
we slowly revved it up until it got to 5900 and as soon as it did we let off,becuz we figured the fuel shutoff should have been around 4000rpm.should we rev it up to 5900 again or should we go to 4000 and hold it there for a couple of seconds?
i appreciate all of the help guys.
charles